1. Field of the Invention
This invention relates to tortillas which may be stored without substantial loss of their flexibility. More particularly, this invention relates to tortillas prepared from a dough comprising wheat flour, water, fat and suitable amounts and proportions of vital wheat gluten and hydrophilic gum which may be stored prior to use without substantial loss of their flexibility.
Tortillas are conventionally made from whole corn kernels which are treated with alkali and then ground to a flour. The flour is combined with water to form an unleavened dough from which thin flat discs are formed and the discs heated. It is also known to prepare tortillas from wheat flour as taught, for example, in U.S. Pat. No. 3,792,174. Whether made from corn or wheat flour, tortillas, which are pliable when fresh, become hard and inflexible when stored for longer than about 24 hours or even a shorter period.
Tortillas are generally used in preparing foods such as tacos, burritos, enchiladas, etc., which require that heated tortillas be folded over or rolled around a filling of diverse food materials. Although a considerable degree of crispness is desirable in tortillas, they should preferably remain sufficiently pliable upon storage to withstand folding or rolling without substantial cracking or breaking occurring in the areas of stress.
2. Discussion of the Prior Act
There are a number of patents relating to tortillas and processes for preparing the same. The problem of retarding staling and maintaining flexibility in stored tortillas is dealt with in U.S. Pat. Nos. 3,653,915; 3,655,385; 3,672,912; 3,687,685; 3,690,893; 3,694,224; and 3,709,696. These patents teach incorporating into dough prepared from nixtamilized corn or corn flour various materials, e.g., mono- and diglycerides, epichlorohydrin, hydrophilic gums, borates or aluminates, inorganic gels, e.g., aluminum hydroxide, etc. U.S. Pat. No. 3,730,732 relates to a process for increasing the yield of dough and tortillas as well as retarding microbiologlical spoilage therein by adding water soluble alkaline substances, e.g., alkali metal hydroxides and bicarbonates, to a nixtamilized corn dough. U.S. Pat. No. 3,853,998 is directed to retarding microbiological spoilage of tortillas by incorporating alkyl esters of para-hydroxybenzoic acid into corn based dough. U.S. Pat. No. 3,859,449 is concerned with retarding or preventing microbiological spoilage of tortillas by adding acetic or propionic acid or their anhydrides to corn flour dough.
U.S. Pat. No. 3,792,174 relates to a dry mix for preparing tortillas comprising wheat flour, baking powder and other materials.
There are also a number of patents relating to the use of hydrophilic colloids and/or gluten in preparing baked goods.
U.S. Pat. No. Re 19,933 teaches the use of hydrophilic colloids in cake batter to improve the keeping quality of cake products. U.S. Pat. No. 3,219,455 is directed to a bread additive comprising vital wheat gluten, a hydrophilic colloid and an oxidizing agent. U.S. Pat. No. 3,271,164 relates to an additive for retarding staling in baked goods comprising karaya gum, carrageenans and algins.
U.S. Pat. No. 4,109,018 relates to a dough composition for making a low calorie diet bread. The dough comprises wheat flour and a number of other materials including vital wheat gluten and a hydrophilic gum. U.S. Pat. No. 3,574,634 is directed to a low-carbohydrate dough consisting of gluten flour containing vital gluten, a cellulosic filler, vegetable gum and water.